1. Field of the Invention
The invention relates to a frame and support element as a composite structure with production largely from aluminium or aluminium-fibre reinforced plastics and similar materials, the extrusion process being used as the method of production.
Such support or frame elements are torsion-resistant and are to be designed in accordance with the strength criteria of the particular field of application. Generally, they are directed toward the possibilities offered by steel in respect of production costs and material properties. The composite structural combination described below has the object of so combining, in the structural unit of a frame or support element, different types of materials to form an integral element that, firstly, the frame or support element simultaneously acquires, exceeding this apparatus function, the property of a multiply differentiatable hollow body which is suitable for the development of the most varied apparatus functions, for example motor drive elements mounted in frames. Secondly, the composite structure should be suitable for so providing any point of force application in the support element that the lines of action of the force pass into the material having the greater strength or into a zone such that the properties of the mutually combined materials effectively complement one another: thus, for example, a thin-walled steel tube, by positive insertion into a double-walled aluminium hollow section member strengthened with longitudinal ribs, may thus lose any degree of freedom for the design of a vibration response. Accordingly, in the design to be determined from the field of application, it is necessary to devise an extremely rigid support and frame component which simultaneously combines in itself in a rational manner, in the form of an integral element, advantages of strength and functional progress which are derived from the purpose of the apparatus and are largely developed in hollow bodies.
This object is achieved in that the hollow section member which has no cross-walls and which is at least partly multiple-walled, is so inserted in closing and composite or combining members applied by pressure against its open ends that each of these closing and connecting members is in positive contact with at least two different shaped parts. These contact zones have a double structure: one at the periphery of the hollow section, as a rule simultaneously representing (in the case of axial contact pressure) the contact zone of closing member/hollow section, the other with greater depth of penetration inside the walls of a hollow-section chamber, which simultaneously enclose within themselves the support (rod) axis. Finally, it is necessary to have another main feature that the formation of cross-walls is accomplished by, or by means of, the closing and composite members, that is either inside the closing-member cavity or with a depth of penetration into the hollow section inside a hollow-section cavity. These closing members braced against one another simultaneously have the property of a composite body from several aspects. Since as a rule they consist of steel sheet or chrome-steel sheet (or nickel-plated plain sheet steel to avoid contact corrosion in respect of aluminium), initially they lie within the high strength values of these materials. It is possible for force-application points to be formed on them, without the need for multiple screw fastenings and material accumulations as for the formation of moments of force on cast aluminium parts. Furthermore, since each force is a vector and is practically always constantly distributed superficially, the lines of force from the load application to the closing member extend well into the material composite field of the rigidly designed support part, in which case the positive or interlocking contact at the periphery and the second positive contact with axial penetration depth have particular significance since thereby the form stability of the aluminium member is brought into the force field. In this way it is possible to control the load at any point of force application even in respect of the longitudinally and transversely acting components, therefore all the combined stresses from tension, compression, bending and torsion. Resistance to torsion may precisely be achieved by providing in addition to the axial pressure also radial pressure, as shown in FIG. 5.